Electrolytic refining of metal



F. L, ANTISELL 1,908,943

May 16, 1933.

- ELECTROLYTIC REFINING 0F METAL Filed June 19, 1929 2 Sheets-Sheet 1 INVENTOR FMLW Patented May 16, 1933 UNITED STATES PATENT OFFICE A FRANK L. ANTISELL, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOB, BY DIRECT MESNE ASSIGNMENTS, TO COPPEBWELD STEEL COMPANY, 01 GLASSPOBT, PENN- SYLVANIA, A CORPORATION OF PENNSYLVANIA ELECTROLYTIC REFINING METAL Application filed June 19, 1929. Serial No. 372,014.

This invention relates tothe electrolytic refining of metal and while one of its pr1nc1- .pal commercial applications is in the refining amount of operating care is required in maintaining the apparatus in operative condition.

I provide for placing in a bath of electrolyte a plurality of pieces of metal to be refined, the several metal pieces substantially isolating one part of the bath from another and passing an electric current through the electrolyte and the metal pieces. Preferably the metal pieces are in the form of flat sheets which have been rolled or pressed to uniform thickness. The bath is preferably contained in an elongated tank of uniform cross section and the plates are cut to such size as to fit nicely within the vessel, extending from side to side thereof and from the bottom to the level of the electrolyte. The several plates form bi-polar electrodes, the impure metal being corroded away on one side and the electrolytically pure metal being deposited on the other side. Some of the impurities go into solution and the remainder are precipitated as slime. It is highly important that the precipitated impurities shall not become mechanically attached to the cathode side of the electrodes, as this results in impure metal. It is also important that the slime shall not repose in the bottom of the tank as this will cause short circuiting and treeing between the electrodes. I overcome this by maintaining a flow and circulation of the electrolyte between the electrodes. This flow is preferably upward since I have found this upward flow to be superior-in maintaining the cathode surfaces free of mechanically attached impurities. Preferably jets are .employed between the electrodes. These jets may extend well down into the bath so that the incoming electrolyte impinges on the bottom of the bath and prevents any slime from reposing there. The electrolyte then flows upwardly and is taken off and filtered. After filtration, the impurities in solution are removed as by Stratification. The filtered electrolyte is then returned to the jets. Provision is also made for moving the jets back and forth across the bath between electrodes so as to insure that all surfaces of the electrodes will be swept clean.

In the accompanying drawings, which illustrate more or less diagrammatically a present preferred embodiment of the inven tion,

Figure 1 is a transverse view through an apparatus for carrying out the invention; an

Figure 2 is a longitudinal section, partly broken away, through the bath.

The apparatus shown in the drawings comprises a tank 2 which may be made of wood and having spaced electrodes 3 arranged therein. The electrodes extend from one side of the tank to the other and from the bottom thereof to the level of the electrolyte. The electrodes employed are made of the metal to be refined and may be produced by any desired process. I prefer, however, to cast them and then subject them to a rolling or pressing operation, as this makes them of uniform thickness and improves the surface.

As a specific example the tank may be.20 inches deep by 14 inches wide by 204 inches long, and may contain 140 electrodes each 7 of an inch thick. Current is supplied from a generator 4 leading through a conductor L to an end electrode 3a, the current thence traveling through the bath and the electrodes to the electrode 36 at the other end of the tank. The electrode 312 is connected to the generator by a conductor L The electrodes are spaced and supported by any desired means, as, for example, porcelain knobs or buttons 5.

- carriage 9, carried by rollers 10. A crank mechanism 11, driven in any desired manner, is efiective for reciprocatin the carriage 9 and thus moving the jets 6 om side to side of the tank.

The electrolyte supplied through the jets 6 flows upwardly between the electrodes, maintaining the cathode surfaces free of mechanically attached slime and also maintaining the tank bottom and sides perfectlyclean;

The excess electrolyte flows over a weir 12 to a launder 13 which discharges it into a filter 14. In order to prevent short circuiting across the top of thebath, baflles 15, made of hard rubber, may be employed. v The filter 14 removes the precipitated impurities and the impurities in solution may thereafter be removed in any desired manner. I have shown a pump 16 which forces the filtered electrolyte through a conduit 17 terminating in a flexible hose 18 which supplies electrolyte to the manifold 7. A branch 19 leads from the conduit 17 to a Stratification tank 20 wherein the impurities in solution are separated by gravity. The pure electrolyte returns to the conduit 17 from the tank 20 through a conduit 21 and the separated impurities are taken off through a conduit 22 to a purifying system 23. A valve 24 is shown in the conduit 19 for controllin the amount of flow to the Stratification tan 20, and a constriction 25 is indicated in the conduit 17 between the conduits 19 and 20 so as to secure a sufiicient pressure difierential to permit of taking off the desired amount of electrolyte for purification through the conduit 19.

In the case of refining the cuprous group of metals, the slime is treated to remove arsenic, antimony, lead, tin, gold, silver, palladium and platinum, while the solution carried to the purifying system 23 is treated to remove nickel, iron and some arsenic.

By my process material savings in operating costs are effected by reason of the reduction of power requirements and labor costs. The units may be continuously operated and need not be periodically shut down for cleaning, as isthe case with present systems. Maintenance and repair costs are reduced to a minimum. Very low grade metals may be employed and a very high quality product is produced. The plant may be of any size and can be erected at a cost which is only a small fraction of the cost where systems now in use are employed. The quantit of electrolyte required per ton of pro uction is yery small and the amount of metal in process 1s also greatly reduced.

I have illustrated and described a present preferred embodiment of the invention. It will be understood, however, that it is not limited to the form shown but may be otherwise embodied or practiced within the scope of the following claims:

I claim:

1. In the process of electrolytically refinng metal, the steps consisting in lacing in a bath of electrolyte a plurality oi metal electrodes to be refined, the electrodes substantially isolating one part of the bath from another, passing an electric current through the electrolyte and the electrodes, discharging between the electrodes a jet of electrolyte, and moving the jet.

2. Apparatus for electrolytically refiningmetal comprising a container, a bath of electrolyte in the container, a plurality of elec trodes of substantially uniform thickness to be refined, the electrodes extending from one side of the container to the other and also extending. from the bottom thereof to substantially the level of the electrolyte, jet .meansfor maintaining a flow of electrolyte between the pieces, and means for moving the et.

3. In the process of electrolytically refining metal, the steps consisting in placing in a bath of electrolyte a plurality of metal electrodes to be refined, passing an electric current between the electrolyte and the electrodes, discharging between the electrodes a jet of electrolyte, and moving the jet.

4. In the process of electrolytically refining metal, the steps consisting in placing in a bath of electrolyte a plurality of metal electrodes to be refined, passing an electric current between the electrolyte and the electrodes, discharging between the electrodes a jet of electrolyte, and moving the jet in a direction other than the line of discharge of the jetted electrolyte.

5. In the process of electrolytically refining metal, the steps consisting in placing in a bath of electrolyte a plurality of metal electrodes to be refined, passing an electric current between the electrolyte and the electrodes, discharging between the electrodes a jet of electrolyte, and moving the jet sidewise.

In testimony whereof I have hereunto set m hand.

y FRANK L. ANTISELL. 

